This invention relates to an electric component with a soldering-less terminal fitment, and more particularly to an electric component with a terminal fitment which permits connection of a connection conductor without soldering.
Use of flon is subject to restriction in view of environmental pollution, so that it is highly required to connect a terminal conductor, a lead wire or the like to a connection electrode of a circuit board without soldering. This is likewise true of an electric component called a focus pack used for adjustment of a focus voltage of a cathode ray tube (CRT), a screen voltage thereof or the like.
U.S. Pat. No. 4,471,339 discloses a high-voltage variable resistor unit including a terminal connection structure for connecting, by means of a terminal fitment like a coiled spring provided at one end thereof with a ring into which a connection conductor or connection terminal is inserted, a connection electrode of the resistor unit to the connection terminal without soldering. Such a conventional terminal fitment as taught in the U.S. patent fails to firmly hold the connection terminal therein, to thereby cause the connection terminal to be readily released or detached from the terminal fitment. Also, it tends to cause a failure in electrical connection between the connection terminal and the terminal fitment. Further, the above-described construction of the terminal fitment requires to keep the connection terminal and connection electrode connected together prior to incorporation of a circuit board in an insulating casing. This, when use of a lead wire of an increased length is required for the connection conductor, causes the long lead wire to obstruct assembling of the high-voltage variable resistor unit. In particular, when the high-voltage variable resistor unit including the terminal connection structure is combined with a fly-back transformer, the high-voltage variable resistor must be placed in a heating oven together with the long lead wire for the purpose of subjecting a resin material for molding of the fly-back transformer to heat curing. Unfortunately, the long lead wire renders the operation highly troublesome and requires to provide a space sufficient to receive the long lead wire therein in the heating oven, leading to a deterioration in production efficiency.
In order to solve the problem, the assignee proposed an electronic or electric component including a terminal fitment for connecting a core of a lead wire to a connection electrode of a circuit board without using any soldering, as disclosed in U.S. Pat. No. 5, 546, 280, which corresponds to Japanese Patent Application Laid-Open Publication No. 318669/1994. The terminal fitment disclosed includes a connection conductor holding section and a contact terminal section of which a proximal portion is formed in a manner to be integral with the connection conductor holding section. The contact terminal section includes a contact portion pressedly contacted with an electrode of the circuit board by elasticity. The contact terminal section includes a curved portion which is projectedly curved in a direction of insertion of the connection conductor therethrough, to thereby provide the contact portion.
Unfortunately, the electric component disclosed in the U.S. patent causes the contact portion on a free end of the contact terminal section to be detached from the electrode on the circuit board due to slippage thereof on the electrode, resulting in a failure in contact often occurring.